The invention relates to electrical machines.
The invention relates more particularly, although not exclusively, to heavy duty electrical machines which are subjected to adverse conditions, are mechanically coupled to machinery in use and are not readily serviceable in situ. Such electrical machines are found in operation in deep mining workings and like environments for example. At present, failure of such machines requires a mechanical decoupling of the machine from a pump, a cutter and the like and disconnection of the machine from an electrical power supply. The electrical machine de-coupling and disconnecting must be carried out by skilled personnel and the machine removed and taken to a service workshop for repair or servicing. This generally results in considerable loss of production time. Even if a spare machine is available in situ, the alignment of the replacement machine, the mechanical coupling and electrical connection can take a considerable time period. It has been found in practice that faults occurring in stators of electrical machines represent a frequent cause of electrical machine failure.
It is an object of the invention to reduce the present problems associated with the occurrence of stator faults.